This invention relates to router tables and fences for use with router tables.
Because of their versatility, electric routers are very widely used in woodworking, particularly in home and small commercial shops. Such routers use a powerful electric motor in a housing to which handles are attached for holding and manipulating the tool. The motor shaft terminates in a collet adapted to receive the shank of a router bit or cutter, and a base attaches to the housing and surrounds the cutter so that a portion of the cutter may protrude beyond the base, which bears against a workpiece during use of the router. The position of the base is adjustable up and down parallel to the rotating axis of the collet and cutter, and in plunge routers the relative position of the base and router cutter can change during use of the tool in order to xe2x80x9cplungexe2x80x9d the cutter into the workpiece. Electric routers are generally intended to be used by moving the router relative to a stationary workpiece, with a portion of the router base bearing against the workpiece.
Substantial additional versatility can be achieved by mounting a router in an inverted position with the router cutter protruding up through an opening in a relatively large, flat work surface to provide, in effect, a shaper. With this arrangement, a workpiece lying on top of the work surface can be manipulated relative to the stationary router and a rotating router cutter, the position of which does not move relative to the workpiece. Such router tables are commercially available in a variety of configurations, and numerous plans for homemade router tables are also available.
Many commercially available router tables are provided with fences, and fences for both commercial and homemade router tables are frequently made by users by clamping or otherwise fixing a length of wood to the router table top. Because most router table operations using a fence require that only a portion of the router cutter protrude beyond the face of the fence, provision typically needs to be made for locating the fence at least partly around the cutter. This is sometimes accomplished by machining a slot or recess in the fence within which a portion of the cutter is positioned.
Such shop-made fences, and many of the commercially manufactured fences, suffer from a variety of deficiencies. For instance, many are difficulty to position, reposition or adjust accurately. Some have insufficient strength to resist deformation during use, and many do not easily accommodate chip and dust removable accessories. It is very typically desirable to use work hold-down and safety shield accessories with router table fences, and many fences accept attachment of such accessories only with difficulty, if at all.
It is thus among the objects of the present invention to provide a router table fence that is straight, rigid, easily adjusted and which accommodates good chip escape.
It is a further object of the present invention to provide a router table fence that can be easily used in jointing a work surface.
It is another object of the present invention to provide a router table fence that will easily accommodate a wide variety of additional shop-made and commercially available accessories.
These and other objects of the present invention will become apparent from the following description of the invention, the accompanying drawings and the claims.
The router table fence of the present invention uses three nesting extrusions or spars, two of which lie under a longer third spar. By positioning the inner ends of the two lower spars adjacent to a router cutter protruding through a router table, it is possible to provide a fence, particularly when the lower spars are used with wood facings, that can be adjusted to closely surround the cutter. Lateral movement of the fence assembly adjusts the amount of cutter that contacts a work piece manipulated past the cutter while contacting the fence.
The cross sectional shapes of the spars are typically identical and are generally square, with structure that permits the upper, longer spar to rest on top of, and be attached in a manner permitting it to slide against, the lower two spars. Tee-shaped slots in each face of the spars accept fasteners that connect the spars together. Such tee-shaped slots also accept fasteners for a variety of accessories, such as hold-down devices and shields. Fence locks attach the fence to a variety of router table tops without the need for fence-receiving structures separately attached to the router table or table top. The fence locks of the present invention can be used for many top thicknesses but work particularly well with thin tops.
A micro-adjust stop can be used in cooperation with the fence locks to make very accurate and predictable adjustments in the position of the fence on a router table top.
Wood sub-fences attached to the lower fence spars can be cut by a router cutter to fit very closely around the profile of the cutter to facilitate chip removal and to reduce tear-out in the work piece. By using a shim behind one of the sub-fences in order to position it parallel to, but slightly offset from, the other sub-fence, it is possible to joint a surface of a board using a xe2x80x9cstraightxe2x80x9d cutter.
Among the shields easily attached to the fence of the present invention is one that can be formed from a single sheet of suitable plastic like polycarbonate or acrylic with a 90xc2x0 bend joining a semicircular (horizontal) portion that lies above the router cutter in use to a rectangular (vertical) portion with two screw-receiving vertical slots for receiving screws that are threaded into nuts within one of the fence tee-shaped slots to mount the shield where needed. The shield can be mounted directly against the fence when the cutter being shielded is in that location. In other instances, particularly where wood sub-fences are used, longer screws can pass through the shield and then through stand-offs that position the shield at a desirable location (above the router cutter) away from the fence.